Wind turbines direct drive alternator system with torque balancing

ABSTRACT

Wind turbine direct drive alternator system includes a supporting structure, at least two turbines mounted on the supporting structure to rotate in opposite directions when exposed to the same wind, a respective number of alternator rotor disks whereby each turbine is directly connected to an alternator rotor disk, and a stator unit having two sides each facing a respective rotor disk. The stator unit is arranged or constructed such that torque generated by rotation of each turbine can be transmitted therethrough with a view toward balancing the torque induced on the supporting structure by rotation of the turbines. When the stator unit includes two stator disks, each stator disk transmits approximately the same magnitude of torque as, but in an opposite direction to, the other stator disk. The two stator disks balance the torque of each other and almost no external torque is needed to balance the system.

FIELD OF THE INVENTION

The present invention relates generally to a wind energy generatingsystem that can be airborne, fixed to a ground-based tower or situatedoffshore, and more specifically to a wind energy generating system thatincludes multiple turbines and a direct drive alternator system that arearranged to minimize and possibly eliminate induced torque on thesystem.

BACKGROUND OF THE INVENTION

In order to produce electricity from a wind turbine, the rotations ofthe wind turbine are typically transferred to an alternator, directly orthrough an intervening transmission system. Output power of thealternator is a result of the multiplication of the rotational speed ofthe wind turbine (in radians per second) by the torque (inNewton-meters) that is acting on a rotor of the alternator.

There is a trend to increase the span of wind turbines in order tocapture more wind power; however, the rotational speed of the windturbines has decreased. As a result, the torque induced by the windturbine on the alternator rotor has increased accordingly. For example,for a 1 mega watt wind turbine rotating at 30 rpm (3.14 radians/second),the torque induced on the alternator rotor while producing 1 MW will be”

Torque=1,000,000 W/3.14 radians/second=318471 Newton-meter=32.5 metrictons. This enormous torque must be balanced by the construction of thewind turbine wherever it is placed, i.e., on the ground, offshore or inthe air.

OBJECTS OF THE PRESENT INVENTION

it is an object of at least one embodiment of the present invention toprovide a wind energy generating system including a plurality of windturbines and an alternator system that are torque balanced, i.e., thetorque that the turbines and alternator induced on other sections of thesystem will be almost zero.

Another object of at least one embodiment of the present invention is toprovide a wind energy generating system with a direct drive alternator,i.e., the does not have a transmissions.

Yet another object of at least one embodiment of the present inventionis to provide a wind energy generating system that can be used withdifferent types of wind turbines, whether mounted to the ground, mountedoffshore over a body of water or airborne.

Still another object of at least one embodiment of the present inventionis to provide a wind energy generating system that will be light-weightand have a relatively low cost to produce.

Accordingly, one embodiment of a wind energy generating system inaccordance with the present invention comprises a supporting structure,at least two turbines rotatably mounted on the supporting structure andarranged to rotate in opposite directions when exposed to the same wind,a respective number of alternator rotor disks whereby each turbine isdirectly connected to one of the alternator rotor disks, and a statorunit including at least two stator disks that are mechanically connectedto or integral with each other such that each stator disk transmitsapproximately the same magnitude of torque as, but in an oppositedirection to, the other stator disk. As such, the two stator disksbalance the torque of each other and almost no external torque is neededto balance the wind energy generating system, with respect to inducedtorque on the supporting structure.

Other and further objects, advantages and features of the presentinvention will be understood by reference to the following specificationin conjunction with the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with further objects and advantages thereof, maybest be understood by reference to the following description taken inconjunction with the accompanying drawings, wherein like referencenumerals identify like elements, and wherein:

FIG. 1 is a side view, partially in cross section, shows turbines and analternator section of a wind energy generating system in accordance withthe invention;

FIG. 2 is a view along line p-p of FIG. 1 through the turbines bladesand shows the profile and angle of the blades;

FIG. 3 is a detailed drawing of segment 100 of the wind energygenerating system shown in FIG. 1;

FIG. 4 is a cross-sectional view taken along line A-A of FIG. 3;

FIG. 5 is an arrangement of one segment of the permanent magnet of thewind energy generating system in accordance with the invention;

FIG. 6 is a front view of one of the rotor disks of the wind energygenerating system in accordance with the invention;

FIG. 7 is a front view of one of the stator disks of the wind energygenerating system in accordance with the invention;

FIG. 8 is a side view of the wind energy generating system operating asan airborne version;

FIG. 9 is a front view of the wind energy generating system, operatingas a ground-based version;

FIG. 10 is a cross-sectional view of the wind energy generating systemshown in FIG. 9 with a connecting element that connects the wind energygenerating system to a ground-based or offshore tower;

FIG. 11 is a side view of the connecting element of FIG. 10;

FIG. 12 is a side view, partially in cross-section, of a secondembodiment of a wind energy generating system in accordance with theinvention which is based on magnetic flux in a radial direction;

FIG. 13 is a partial view of the turbine section of the wind energygenerating system showing another embodiment of a stator unit inaccordance with the invention;

FIG. 14 is a partial view of the turbine section of the wind energygenerating system showing yet another embodiment of a stator unit inaccordance with the invention;

FIG. 15 is a schematic of one electricity processing system thatdelivers DC current from the wind energy generating system in accordancewith the invention; and

FIG. 16 is a side view, partially in cross-section, of anotherembodiment of the wind energy generating system in accordance with theinvention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the accompanying drawings wherein the same referencenumerals designate the same or similar elements, a wind energygenerating system in accordance with the invention is designatedgenerally as 10 and comprises two turbines, each including two turbineblades 107 and 117, and which turbines are arranged to have oppositerotational directions when exposed to the same wind. Additional turbinesand turbine blades may be provided.

Wind turbine blades 107 and 117 are connected to hubs 109 by connectingelements 108, and wind turbine blades 107 are connected through a hub109 to a front bearing housing 110 while wind turbine blades 117 areconnected through a hub 109 to a rear bearing housing 114. The bearinghousings 110 and 114 allow the turbines with turbine blades 107 and 117,respectively, to rotate freely around a rotation axis defined by a mainshaft 115 and transfer their rotational motion to rotor disks 104.Bearings 111 are placed inside the bearing housings 110 and 114 toenable rotation of the bearing housings 110 and 114 relative to the mainshaft 115. Bearings 111 may be conical type bearings, or other type ofbearings that can support axial and radial forces. The main shaft 115has a hole 113 therein through which electrical wires (not shown) maypass, for example as shown by wires 175 and 176 in FIG. 16.

Wind energy generating system 10 also includes alternators components.The segment designated 100, enlarged in FIG. 4, shows a segment of apermanent, rotor magnet 103, a rotor disk 104, a stator magnetic core101, a pre-winding coil 102 and a stator disk 105. The stator magneticcore 101, in this embodiment of the system, has a generally C-shape andit can be produced by any of the following technologies: laminations,c-cores, unicore and other technologies that are known in the industry.The pre-winding coil 102 can be assembled on the magnetic core 101, andthis method will make the stator winding process more economical, butother methods of coil winding can be used. The combination of the statormagnetic core 101 and the pre-winding coil 102 constitute a conductivecoil assembly. Each rotor disk 104 is arranged relative to the facingone of the stator disks 105 such that the magnets 103 on the rotor disks104 generate a magnetic field that encompasses the conductive coilassemblies on the stator disk 105.

Rotor magnet 103 is one of the system's permanent magnets which will beshown in detail in FIG. 5. The wind generating system 10 includes atleast two rotor disks 104, shown in detail in FIG. 6, each rotor disk104 is arranged to be rotated upon rotation of a respective wind turbinewith turbine blades 107 or 117. Wind generating system 10 also includesat least two stator disks 105, shown in detail in FIG. 7, each of whichis at least partly opposed to a disk-shaped portion of a respectiverotor disk 104.

Connecting elements 106 are arranged between the at least two statordisks 105 and transfer the opposite directional torques between thestator disks 105 and enable the torque-balancing in accordance with theinvention. The number of connecting elements 106 can vary and in theillustrated embodiment of the invention, there are eight connectingelements 106. The shape of the connecting elements 106 can vary and inthe illustrated embodiment, they have a substantially cylindrical shape.Thus, different numbers and shapes of connecting elements are envisionedin the invention.

A supporting cylinder 112 connects the stator disks 105 to the mainshaft 115. Supporting cylinder 112 allows a center positioning of thestator disks 105 and the rotor disks 104 relative to each other, as wellas connection of the wind generating system 10 to a ground-based oroffshore tower, shown in detail in FIGS. 9-11.

Magnetic cores and/or coils 119 are placed around the stator disks 105,represented by dotted lines. Also, permanent magnetic elements 120 areplaced around the rotor disks 104, also represented by dotted lines.

FIG. 2 shows a cross-sectional profile and angular position of theturbine blades 107 and 117 along line p-p in FIG. 1. The profile of theturbine blades 107 and 117 is preferably identical. However, the angleof attack of the turbine blades 107 and 117 relative to a direction ofthe wind 135 is different from one another and arranged to produceopposite rotational movement in that the turbine with turbine blades 107rotates in the direction of arrow 116 while turbine with turbine blades117 rotates in the direction of arrow 118 while exposed to wind in thesame direction 135.

FIG. 3 shows segment 100 of FIG. 1 including one magnetic core 101, twopre-winding coils 102, two permanent magnets 103, a plate 121, part ofthe stator disk 105, and part of the rotor disk 104. Plate 121 maycomprise iron. The magnetic core 101 is preferably made from laminationsof silicon steel, that provide the magnetic core 101 with a generallyU-shape with the pre-winding coils 102 being placed around the two armsof the U-shaped magnetic core (see FIG. 4). The number of windings andthe cross-sectional area of the winding wire can be adjusted accordingto the electrical requirements of the alternator. The U-shaped magneticcore 101 and the pre-winding of coils thereabout allow a more accurateand more economical production process of the coils. Other windingtechniques and magnetic core shapes can be used in the invention.

FIG. 4 shows segment 100 in a cross-sectional view along line A-A inFIG. 3. Permanent rotor magnets 103 are attached to the plate 121, e.g.,affixed or glued thereto, to provide the configuration shown in FIG. 5.The permanent rotor magnets 103 are preferably NDFeB type magnets thatare very strong permanent magnets, although other types of magnets canbe used. The assembly of two permanent rotor magnets 103 on the plate121 is designed to create a maximum magnetic flex through the magneticcore 101, when the two permanent rotor magnets 103 are positioned nextto the arms of the U-shaped magnetic core 101.

FIG. 6 shows the rotor disk 104 with a plurality of magnetic assembliesconnected to an annular portion thereof, with each assembly comprising aplate 121 and two permanent rotor magnets 103 affixed thereto. Thematerial of the rotor disk 104 is preferably aluminum, fiber glassand/or carbon fiber, although other materials can be used. The plate 121may be omitted in some embodiments so that the permanent rotor magnets103 are attached directly to the rotor disk 104, e.g., glued thereto.Reference 122 designates the locations of the other magnetic assembliesthat are not shown in FIG. 6. In the illustrated embodiment, an angle125 between the centers of adjacent ones of the magnetic assemblies isabout ten degrees. A center hole 123 of a central portion of the rotordisk 104 fits the outside diameter of a mating portion of a respectiveone of the bearing housings 110 and 114 (see FIG. 1). Holes 124extending through the rotor disk 104 enable the rotor disk 104 to beconnected to the bearing housings 110 and 114. Spoke portions connectthe central portion with the center hole 123 to the annular portion towhich the magnet assemblies are mounted. The wind energy generatingsystem 10 in accordance with the present invention has at least tworotor disks 104, and the source of the magnetic flux of the rotor disks104 is preferably permanent magnets but other type of magnets such aselectromagnets can be used.

FIG. 7 shows a front view of the stator disk 105, which in thisembodiment has a plurality of pairs of rectangular holes 126 in anannular portion. Magnetic cores 101 are attached to the stator disk 105such that the arms of each magnetic core align with and possibly extendthrough a respective pair of holes 126 (see FIG. 4). Other methods forattaching the magnetic cores 101 to the stator disk 105 can be used inthe invention and as noted above, other shapes and forms of magneticcores can be used. The stator disk 105 itself can be formed as part ofthe magnetic cores. In one embodiment, coils without magnetic materialsare attached to the stator disk 105.

A center hole 130 of a central portion of each stator disk 105 fits theoutside diameter of supporting cylinder 112. Holes 131 extending througheach stator disk 105 enable each stator disk 105 to be connected to thesupporting cylinder 112. Holes 132 are used to connect the connectingelements 106 to the stator disks 105 so that via the connecting elements106, the two stator disks 105 are connected to one another to allowtorque to be transmitted from one stator disk 105 to the other.

Instead of constructing the stator disks 105 as separate units, eachmounted about the supporting cylinder 112, it is possible to constructthe two stator disks 105 as one stator unit. For example, FIG. 13 showsthe stator unit 106A as an integral unit with two disk-shaped portionson lateral sides wherein one disk-shaped portion 106B has a faceoriented toward one rotor disk 104 and the other disk-shaped portion106C has a face oriented toward the other rotor disk 104 and integralconnecting struts 106D extend therebetween. Another envisionedconstruction of the stator unit is as a single disk-shaped member 106Eas shown in FIG. 14, one side of which faces one rotor disk 104 and theother side of which faces the other rotor disk 104 so that connectingelements 106 are not necessary. However, in one or both of theseembodiments, each section of the stator unit, which may be considered asa stator disk, should have sets of coils that are exposed to magneticflex from a rotating rotor while at least two rotor disks are rotatingin opposite directions. Thus, the stator unit defines two disk-shapedportions each facing a respective rotor disk 104, whether on the sameintegral member or separate members that are connected together.

The angles between the centers of the magnetic cores are designated 127,128, and 129. In the illustrated embodiment, there are twelve sets ofmagnetic cores, so that when the angles 127, 128, 129 are equal, theyall equal thirty degrees. If the angles are not equal, e.g., angle 127is 33 degrees, angle 128 is 36 degrees and angle 129 is 21 degrees, low,no-load idle resistance of the system is obtained because all magnetsand magnetic cores will not be at same maximum attraction angularposition together. This angular differential arrangement will cause adifferential in the phases of the output of the coils. The outputelectricity of the system can be multi-phase AC or each conductive coilassembly can be converted to DC and all of the DC outputs can beconnected in a serial connection.

To this end, with reference to FIG. 15, a plurality of conductive coilassemblies 160 is shown and each is connected to a respective rectifier162. Each rectifier 162 has a positive and negative output with thenegative output of one rectifier 162 being connected to the positiveoutput of another rectifier 162, in serial, with a single positive andnegative output being provided from all of the rectifiers 162. Thisconstruction will result in a high DC voltage output.

The number of magnetic assemblies and the number of the magnetic corescan vary from those shown in the drawings so that any number of magnetsand magnetic cores can be used in the invention.

Referring now to FIG. 12, in the embodiments described above, themagnetic structure is arranged to generate magnetic flux is an axialdirection. In the embodiment shown in FIG. 12, the magnetic structure isarranged to generate magnetic flux in the radial direction. Differencesbetween this embodiment and the embodiments described above lie primaryin the magnetic structure and otherwise, the same components of the windenergy generating system 10 may be used in this embodiment. Thisembodiment includes at least two rotor disks 204 rotatably mounted abouta central shall represented by line 215, permanent rotor magnets 203arranged on the rotor disks 204, two stator disks 205 fixedly mounted tothe central shaft, connecting elements 206 that connect the stator disks205 together, a plurality of magnetic cores 201 arranged on the statordisks 205, and pre-winding coils 202 arranged in connection with themagnetic cores 201. The connecting elements 206 function like connectingelements 106 to connect the stator disks 205 together to allow torque tobe transmitted between the stator disks 205. The operations andtorque-balancing in this embodiment are the same as explained above,with the main difference being that the direction of the magnetic fluxis radial because the magnetic cores 201 are radially outward of therotor magnets 203.

FIG. 8 shows the wind energy generating system 10 of the presentinvention operating as an airborne wind turbine. To this end, a liftingsection 144 is coupled to the wind energy, and lifting section 144 maybe a blimp containing a lighter-than-air gas such as helium. The liftingforces that act on the blimp are a floating force that thelighter-than-air helium creates, and the lift that is created by theaerodynamic shape of the blimp when acted upon by wind. The liftingforces of the blimp are transmitted through tethers 142 and 143 to thewind energy generating system 10 allowing the wind energy generatingsystem to be airborne and operate at high altitude. Construction element140 is interposed between and connects the main shaft 115 to the tether143 and is arranged to cause the center of gravity of the airbornesystem to be lower than a virtual line connecting a point at which thetether 141 is connected to the wind energy generating system 10 and apoint at which the tether 143 is connected to the wind energy generatingsystem 10. As such, this position creates a pendulum effect that keepsthe wind energy generating system 10 balanced with respect to torque.Tether 141 is connected to a winch 145 on the ground.

FIG. 9 shows the wind energy generating system 10 operating on theground (or offshore) at an upper end of a vertical member 150 that maybe any type of pole or tower that anchors the main shaft 115 to theground or to the sea floor. This anchoring may be achieved using a base151 and connecting screws 152,

FIGS. 10 and 11 show exemplifying structure that may be used to supportthe main shaft in a fixed position relative to the ground or sea floor.The connecting structure includes a connecting element 155 thatinteracts with the supporting cylinder 112 that is fixedly mounted tothe main shaft 115. The connecting element 155 has a lower portiondefining a groove in which the supporting cylinder 112 rests and anupper portion that covers the supporting cylinder 112 and each of thelower and upper portions has flanges with holes 156 through whichconnecting members, such as screws, are placed to connect the lower andupper portions together with the supporting cylinder 112 and thus themain shaft 115 fixedly supported therebetween.

Referring now to FIG. 16, in this embodiment of the invention, the rotorassembly has only a single rotor disk 104 and the remaining structure toprovide for rotation of the rotor disk 105 upon rotation of the turbineincluding turbine blades 107 is the same as in the embodiment shown inFIG. 1. However, instead of another rotor disk 104 or other rotor memberand a stator unit including a pair of stator disks 105, the embodimentshown in FIG. 16 includes a second rotating assembly that serves thesame function as the stator disk 105 in the embodiment shown in FIG. 1.This second rotating assembly includes a single member such as a disk105A that rotates relative to the rotor disk 104 and in an oppositedirection thereto, e.g., while the front turbine including turbineblades 107 causes rotation of the rotor disk 104 in one direction whenexposed to wind via the bearing housing 110, the rear turbine includingturbine blades 117 causes rotation of the disk 105A in an oppositedirection via the bearing housing 114 when exposed to the same wind. Asin the embodiments described above, the rotor disk 104 includes magnetsand associated structure and encompassing variations, and the rotatingdisk 105A includes conductive coil assemblies that were provided on thestator disk 105 in the embodiments above. The rotor disk 104 androtating disk 105A are spaced apart such that the conductive coilassemblies and magnets are within a magnetic field of one another.

The electricity that is generated in the conductive coil assemblies onthe disk 105A can be directed to pass through rectifiers described inconnection with FIG. 15 and conducted to two conductive rings 173 and174 arranged on the bearing housing 114. The DC electricity is thenconducted through two conductive brushes 171 and 172 that are arrangedin a non-conductive cylinder 177 fixed to the main shaft 115. Theelectricity passes through wires 175 and 176 connected to the brushes171 and 172 for use and/or storage.

The combination of the single rotor disk 104 with magnets and singlerotating disk 105A with conductive coil assemblies may be repeated onthe same shaft 115.

Advantages of this embodiment of the invention include: by arranging theconductive coil assemblies on a rotating disk 105A (as opposed to on thenon-rotational stator disk 105) and causing this rotating disk 105A torotate in an opposite direction to the rotor disk 104 and such that theconductive coil assemblies are within a magnetic field range of themagnets on the rotor disk 104, the relative velocity between the magnetson the rotor disk 104 and the conductive coil assemblies on the rotatingdisk 105A is doubled. Since the power of the alternator is proportionalto this relative velocity, a higher power from the same alternator canbe achieved or a lower cost alternator can be built while achieving thesame power (in comparison to a case wherein the alternator is associatedwith a construction wherein a stator disk with the conductive coilassemblies is non-rotational relative to the rotor disk). Anotheradvantage is that lighter alternators can be built according to thisembodiment, which is important for airborne wind turbines, as well asfor ground-based and off shore wind turbines. Yet another advantage isthat the opposite directional torques are being transferred from therotor to the rotating disk and from the rotating disk to the rotorelectrically, without need of special construction elements.

It is to be understood that the present invention is not limited to theembodiments described above, but includes any and all embodiments withinthe scope of the following claims. While the invention has beendescribed above with respect to specific apparatus and specificimplementations, it should be clear that various modifications andalterations can be made, and various features of one embodiment can beincluded in other embodiments, within the scope of the presentinvention.

1. A wind energy generating system, comprising: a supporting structure;at least two turbines arranged on said supporting structure to rotate inopposite directions when exposed to the same wind; at least two rotordisks, each rotatably connected to one of said turbines such that saidat least two rotor disks rotate in opposite directions when said atleast two turbines are exposed to the same wind; and a stator unitincluding first and second sides, each facing a respective one of saidrotor disks, said stator unit being arranged such that torque generatedby rotation of each of said turbines can be transmitted through saidstator unit with a view toward balancing the torque induced on saidsupporting structure by rotation of said turbines.
 2. The system ofclaim 1, wherein said supporting structure comprises a main shaft thatdefines a rotation axis about which said turbines rotate, furthercomprising: bearing housings rotatably mounted on said shaft; and hubsfor connecting said turbines to said bearing housing.
 3. The system ofclaim 1, further comprising: magnets arranged on said rotor disks; and aplurality of conductive coil assemblies arranged on said stator unit;each of said rotor disks being arranged relative to said first or secondside of said stator unit such that said magnets on said rotor disksgenerate a magnetic field that encompasses said plurality of conductivecoil assemblies on said first or second side of said stator unit.
 4. Thesystem of claim 3, wherein each of said conductive coil assembliescomprises a magnetic core and at least one coil wound on said magneticcore.
 5. The system of claim 3, wherein each of said conductive coilassemblies comprises a generally U-shaped magnetic core and a pair ofcoils each wound on a respective arm of said U-shaped magnetic core. 6.The system of claim 5, wherein said magnets on said rotor disks arearranged in pairs, further comprising a plurality of plates, each ofsaid plates being connected to a respective pair of said magnets andbeing fixed to one of said rotor disks.
 7. The system of claim 3,wherein said magnets are permanent magnets.
 8. The system of claim 3,wherein said rotor disks and said stator unit are arranged relative toone another such that said magnets on said rotor disks and saidconductive coil assemblies on said stator unit are spaced apart from oneanother in an axial direction of said supporting structure.
 9. Thesystem of claim 3, wherein said rotor disks and said stator unit arearranged relative to one another such that said magnets on said rotordisks and said conductive coil assemblies on said stator unit are spacedapart from one another in a radial direction of said supportingstructure.
 10. The system of claim 3, further comprising a plurality ofrectifiers, each associated with a respective one of said conductivecoil assemblies, said rectifiers being arranged in serial to obtain asingle DC voltage output.
 11. The system of claim 3, wherein saidconductive coil assemblies are distributed around a periphery of saidfirst and second sides of said stator unit at a predetermined angularspacing such that all of said conductive coil assemblies on at least oneside of said stator unit are not directly opposite a respective one ofsaid magnets on a facing one of said rotor disks in a maximum attractionstate to thereby obtain low idle resistance between said rotor disks andsaid stator unit.
 12. The system of claim 1, wherein said stator unitcomprises two separate stator disks each defining one of said sides ofsaid stator unit, said sides being disk-shaped, said stator disks beingrigidly connected together.
 13. The system of claim 12, wherein each ofsaid stator disks includes an annular portion, further comprising aplurality of conductive coil assemblies circumferentially spaced fromone another around said annular portions of said stator disks.
 14. Thesystem of claim 12, further comprising connecting elements arrangedbetween said stator disks to connect said stator disks together andtransfer opposite directional torques between said stator disks andenable the torque-balancing.
 15. The system of claim 1, wherein saidstator unit is an integral structure that includes a first disk-shapedportion defining said first side and a second disk-shaped portiondefining said second side, and integral connecting elements connectingsaid first and second disk-shaped portions together.
 16. The system ofclaim 1, wherein said stator unit consists of a single disk-shapedmember having opposed outer later surfaces that define said first andsecond sides of said stator unit.
 17. The system of claim 1, whereinsaid supporting structure comprises a main shaft that defines a rotationaxis about which said turbines rotate, further comprising a supportingcylinder that connects said stator unit to said main shaft.
 18. Thesystem of claim 1, wherein each of said rotor disks includes an annularportion, further comprising magnets circumferentially spaced from oneanother around said annular portion of said rotor disks.
 19. The systemof claim 1, further comprising a lifting section coupled to saidsupporting structure for enabling said supporting structure to have anairborne state.
 20. The system of claim 1, wherein said supportingstructure comprises a main shaft that defines a rotation axis aboutwhich said turbines rotate and a vertical member arranged to elevatesaid main shaft from a ground surface or floor of a body of water,further comprising: a supporting cylinder that connects said stator unitto said main shaft; and a connecting element that interacts with saidsupporting cylinder and said vertical member to securely support saidsupporting cylinder and thus said main shaft on said vertical member.21. A wind energy generating system, comprising: a supporting structure;at least two turbines arranged on said supporting structure to rotate inopposite direction when exposed to the same wind; at least one firstrotating assembly rotatably connected to a first one of said turbines,each of said at least one first rotating assembly comprising magnets;and at least one second rotating assembly rotatably connected to asecond one of said turbines such that said at least one second rotatingassembly rotates in an opposite direction to said at least one firstrotating assembly when said at least two turbines are exposed to thesame wind, each of said at least one second rotating assembly comprisingconductive coil assemblies; said first and second rotating assembliesbeing arranged relative to one another such that a relative velocitybetween said magnets on said at least one first rotating assembly andsaid conductive coil assemblies on said at least one second rotatingassembly is approximately a sum of a rotational velocity of said firstand second rotating assemblies, whereby said first and second rotatingassemblies induce approximately the same torque in opposite direction oneach other with a view toward balancing torques induced on saidsupporting structure by rotation of said turbines.
 22. The system ofclaim 21, further comprising a plurality of rectifiers, each associatedwith a respective one of said conductive coil assemblies, saidrectifiers being arranged in serial to obtain a single DC voltage outputfrom AC electricity outputs of said conductive coil assemblies.